Gauging system for press brakes

ABSTRACT

Gauges for press brakes and a control system having a plurality of adjustable gauge arms, each of which is pneumatically controlled for movement into effective and non-effective positions automatically upon selected sequential operation of the press.

' [22] Filed:

United States Patent Hirsch 1 1 GAUGING SYSTEM FOR PRESS BRAKES [72]Inventor: Roger B. Hirsch, 2034 W. Fulton St., Chicago, 111. 60612 March5, 1970 [21] Appl. No.: 16,669

[451 Dec. 5, 1972 2,782,831 2/1957 Todd, Jr. ..72/461 2,627,890 2/1953Lloyd et a1 ..72/461 2,924,260 2/1960 Guarino ..72/36 3,465,561 9/1969l-lanni ..72/36 2,669,276 2/1954 Humphrey ..72/455 3,580,023 5/1971Merrill et al ..72/461 Primary Examiner-Lowell A. Larson Attorney-MartinFaier [5 7] ABSTRACT Gauges for press brakes and a control system havinga plurality of adjustable gauge arms, each of which is pneumaticallycontrolled for movement into effective and non-effective positionsautomatically upon selected sequential operation of the press.

25 Claims, 10 Drawing Figures GAUGING SYSTEM FOR PRESS BRAKES Theinvention relates to a control system for the gauge arms on a pressbrake, which are designed forautomatic or selective positioning intoeffective and noneffective positions. In the use of a press brake, it isfrequently desired to perform a plurality of bends in a sheet ofmaterial. l-Ieretofore, it has been necessary to manually locate oradjust the gauges for repeat operations to obtain a plurality of bendsin a single sheet or several sheets. i

In the present disclosure, there is taught a plurality of sets of gaugesdesigned to be automatically set in effective or non-effectivepositions. Each gauge has associated with it a pneumatically actuatedpistoncylinder assembly, each or some of which may be selectivelyactuated in a programmed fashion to carry an associated gauge arm out ofand into effective position. More specifically, the press brake may beprovided with a plurality of sets of three each of gauges, one set ofwhich is connected through its own manifold to a .source of pneumaticpressure, another set of which is also connected through anothermanifold with a source of pneumatic pressure, and the third set of whichis not connected to said source.

These sets of gauges are arranged longitudinally to the rear of theanvil die of the press brake, and, because three or more sets of thegauges may be provided at each station of the press brake, the operatoror operators can progressively advance a sheet of material from one setof gauges to the other in a predetermined programmed fashion forobtaining a plurality of bends in the sheet, i.e., one bend at eachstation during each stroke of the press, without manual adjustment ofthe gauges. The operation of the pneumatic cylinders is electricallycontrolled automatically in a step by step operation, or at the optionof the operator in a non-automatically sequenced mode, as hereinaftermore specifically described.

It 'is an objectof this invention to provide a press brake with novellyconstructed gauge assemblies.

Another object is to provide "gauges of novel construction.

Another object is to provide novel means'for moving the gauge armsselectively into effective and non-effective positions.

Another object is to provide novel electrical means for controlling thepositions of the gauges automatically.

Another object is to provide control means, automatic in its operationfor facilitating sequential production of multiple bends in sheetmaterial or other related sequential press operations.

Another object is to provide an assemblage of the character referred towhich is not difficult to manufacture or install and that mayselectively be operated in a manual or automatic mode and is veryefiicient in use.

Another object is to provide a novel method for setting and actuatingpress brake gauges.

Other objects and advantages of the invention will become apparent withreference to the following description and accompanying drawings.

In the drawings:

FIG. 1 is a front elevational view of a press brake embodying thefeatures of the invention.

FIG. 2 is a rear elevational view thereof.

FIG. 3 is a fragmentary plan view of the back bar showing the novelgauges thereon.

FIG. 4 is a vertical sectional view of the back bar showing a gauge inoperable position in side elevation, and in inoperable position indotted lines.

FIG. Sis a sectional view of a modified form of back bar incorporatingmanifolds for the air lines.

FIG. 6 is a top plan view of a close finger accessory.

FIG. 7 is a top plan view of a modified close finger accessory.

FIGS. 8 and 8A are schematic views of the electrical circuitry for thegauge control system.

FIG. 9 is a view of the control panel.

Referring to the exemplary disclosure of the invention shown in theaccompanying drawings, and particularly to FIGS. 1 and 2, thepress brake11 includes a lower die or anvil l2, and an upper verticallyreciprocable punch or die 13. These two dies extend parallel to oneanother the width of the press brake and are located on the front sidethereof. In operation, a sheet of material, such as sheet steel, is laidon the lower die or anvil 12 with its leading edge extending into thepress brake a distance determined by the ultimate location of a bend tobe produced therein when the upper die is carried downwardly into tightengagement with the lower die. The upper die 13 is periodicallyreciprocated under manual control, or under automatic control by means,of electrical components to be described presently; and the press brakemay be actuated by hydraulic, hydra-mechanical or mechanical means.

The distance to which the sheet is inserted over the anvil die 13 isdetermined by the setting of one or more gauges, generally indicated at14. As best shown in FIGS. 2 through 4, there are a number of gauges 14mounted for longitudinal adjustment along a back 'bar 15 that bridgesthe press brake rearwardly of the mating dies 12 and 13. These gaugesare all alike and the following language describing one of them appliesto all the gauges. Depending upon the width of the sheet material to bebent, gauges 14 may be provided in sets of one or more, with asufficient number provided in each set to allow the operator to insertthe material from the front of the machine over the lower die 13 againstthe gauges in a firm fashion so that the material is exactly alignedwith the position of the intended bend.

Each gauge 14 includes a yoke 16 that is longitudinally slotted andadjustable to secure the gauge to the back bar 15, as by clamp bolt 17.The yoke is longitudinally channelled on its upper face and at its frontend, as at 18, to receive seated in said channel a flop arm 19 that ispivoted at its rear, as at 21, to the yoke 16, so as to be swingable ina vertical plane. The free forward end of the flop arm has a bearingenlargement 22 into which is threaded a gauge screw 23. The screw 23 hasmicrometer markings 24 thereon that register with a marking index edge25 on the bearing enlargement, and it is locked in place by clamp screw19a.

When the flop arm 19 is in the full line position shown in FIGS. 3 and4, the lead edge of sheet 26 inserted between the dies abuts one of saidgauge screws 23 to limit its inward movement. Upward displacement of thegauge bar flop arm 19, when abutted by the sheet, is prevented byoffsetting the stop face of the flop arm below the pivot point 21. Gaugeassembly adjustment is initially accomplished by adjustmentof the yokeon back bar 15, and then adjustment of gauge screw 23 affords preciseadjustment as to determine the exact location of the formation of thebend to be developed in the sheet when the dies are brought together.Because it may be and frequently is desired to provide a number ofspaced formations in the sheet upon successive operation of the dies,the gauges may be provided in set of three each as shown, and at leasttwo gauges may be provided with means to render them non-effective ashereinafter specifically described.

Each of the gauges 14 of each set are individually adjusted tocorrespond with the intended location of a formation in the sheet. Tothis end, as best shown in FIG. 3,- one ofthe gauges 14A is in the downor active position through signal from the electronic system. A secondgauge 14B is in an up or inactive position. The third gauge 14C isphysically located furthest from the die 12. This gauge 14C is notconnected to the manifold to cause the units to remain in the loweredposition at all times.'ln operation, one active gauge may be loweredinto position to form a particular formation while the second gauge isin the upward position, and the third gauge is in the lowered position.Since the third gauge is furthest back from the die 12, the lead edge ofsheet 26 will not contact this gauge unless all active gauges are in theup position. This allows three different bend sizes at any area of themachine.

To accomplish successive movement of flop arms on gauge b'ars 14A and148 into their non-effective positions, each gauge is provided withcylinder 27 having its piston rod 28 located below the respective floparm and just forwardly of pivot 21 and in substantial contact therewith.Located on the inside of the press brake is a set of solenoid valves58-73 (shown in FIG. -2) having a pair of independent leader pipes 31,32 communicating therewith. One of these pipes, e.g., pipe 31, isconnected by flexible conduit 33 to cylinders 27 associated with gauge148. Other flexible conduits 34 connect pipe 32 with cylinders 27associated with gauge 14A. Normally, these piston-cylinder assembliesretain the flop arms in the elevated positions shown in dotted lines(FIG. 4), and when pressure in the associated conduit and cylinder isrelieved, as to withdraw rod 28 from the associated flop arm 19, theflop arm drops by gravity into its effective position. The cylinderassemblies may be air or hydraulically actuated, or actuated by othermeans.

In lieu of leader pipes 31, 32, the back bar may be formed as shown inFIG. 5. Here the back bar a is extruded with a pair of conduits 37connected with cylinder 29, and the plurality of flexible conduits 33a,34a, lead therefrom to the various cylinders.

In operation so far as described, assuming flop arms of gauge 14A to bedown, when the first bend has been made in sheet 26, while the sheet isabutted against said gauge bar 14A, means is actuated automatically ormanually to admit air pressure into cylinder 27 of gauge 14A. Thiscauses flop arm on gauge 14A to be raised into substantially verticalposition, shown in dotted lines in FIG. 4. Air is exhausted fromcylinder 27 of gauge 143 to permit it to fall into effective position.The sheet 26 is then advanced into the dies until its lead edge contactsgauge 148. The press is then cycled to generate the second bend therein.Following making the second bend, air pressure is admitted into cylinder27 of gauge 14B, whereupon flop arm 19 thereof is elevated (and flop armon gauge 14A remains elevated). The sheet 26 is again advanced intoabutment with gauge 14C which has remained in horizontal position (sincethe same has no air pressure connection), and the press cycle isrepeated. Should the sheet 26 be of considerable length, a plurality ofthe sets of gauges may be utilized to maintain alignment.

FIG. 6 shows one form of a close finger accessory 41 that is removablyand adjustably secured to the flop arm 19 for use when close tolerancesand the form and configuration of the flange on the material requiresspacing of the bend from the free end 44 of the finger rather than fromthe screw 23. As shown, the accessory 41 comprises a strap of sheetmaterial, preferably of stainless steel, that has its tail end securedby a stud-nut 42 to the flop arm 19 and has its forward free end bentdownwardly, as at 43, and then forwardly, as at 44, on the axial centerof the micrometer screw 23, thus formed to permit its end 44 to seat onthe rear margin of the die 12.

In the modified close finger accessory shown in FIG. 7, the lower die 12is slotted, as at 46, to receive the front end or finger 47 of the closefinger accessory 48, which is secured as by nut-bolt 49 to the flop arm19. This accessory affords means for gauging a sheet 26, shown in brokenlines, at the cut out corners thereof, to assume close tolerance at thelocation of the intended bend.

Operation of the press brake preferably is automatic, so that itmayfunction in repeat cycles without manual adjustment or positioning ofthe gauges. Means is also provided to manually displace the flop arms,and such manual displacement, as well as automatic operation, is bestcontrolled electrically such as by useof the circuitry disclosed inFIGS. 8 and 8A.

As shown in FIG. 8A, current is supplied from. a service line throughleads-5 1 and 52 which terminate at terminals 53 and 54 in a socket-plugassembly 55.

For manual operation, a manual-automatic switch 76 (see (FIG. 8) ismoved downwardly into manual position to open switch element 760 andalso open automatic switch element 77. Now, to energize solenoids 58 toclose main line 32 so that flop arms 19 connected therewith drop down,control switch 59 (FIG. 8A) in front control box 61 (FIG. 1) is closedmomentarily. This energizes the relay coil in latch relay 62 whichfunctions to close lower contacts of switches 63-64 to deliver currentthrough switch 63 to solenoid 58, energizing same and exhausting line32. The other switch 64 is connected through line 65 to limit switch 66through plug-socket terminal 67. This limit switch 66 is mountedpreferably on the side of the press brake, as shown in FIG. 1, forengagement when the press is operated, although it may be mounted at anyconvenient location on the brake so that it is mechanically located tobe tripped and thus energized during the second half of each stroke ofthe press; or it may be coupled with a signal relay and incorporatedinto the circuitry of the press as to be energized during the secondhalf of each stroke of the press. When the press completes one cycle ofoperation, switch 66 opens momentarily to cut off power to relay 62.

To engage manually another set of gauges, i.e., those connected to fluidline 31, control switch 68 in front control box 61 is closedmomentarily, to energize relay coil 69, which functions to close lowercontacts of switches 71-72 to deliver current through switch 72 tosolenoid 73, thus energizing same and exhausting line 31. The otherswitch 71 is connected by line 74, through plug-socket terminal 75, tolimit switch 66, which operates to cut off current to relay 69 after oneoperating cycle. In this manner the system can be manually operatedduring successive cycles of press operation. These manual cycles can beeffected even though the press has been operating under automaticconditions,'which will now be described.

For automatic operation, the automatic-manual switch 76-77 is in theposition shown, that is with the middle and upper switch blades of eachin contact with the other, and power delivered to a stepper switch 78through line 79. A pulse switch 81 is connected to a pilot light 82through switch 76 and pulse switch 83 in line 84. At the same timecurrent flows through a reset switch 85 to a start indicator lamp 86.

Current is delivered to the stepper sweep arm 78a through line 87. Atthe start, thearm 78a is in engagement with tap which is connected byline 88 to the center terminal 89a, ofthe first of a series (four shown,but any number can be incorporated into the system) of switches 89. Allsolenoid valves are in open position at this time so that all of thecontrolled gauge flop arms plugged into both conduits are in their upsubstantially vertical positions. This series of switches 89 (preferablyfifteen in the embodiment illustrated) are mounted in a control panel 91(see FIG. 9) which has a series of control buttons 92, one for eachswitch. The center blade 89a of switch 89 is moved down into contactwith the lower blade 89b to complete a circuit from tap 0 through theswitch, line 93, tap 75 in the plugsocket 55, from where a lead 94 goesto the fluid line solenoid 73 to energize the same and cause theconnected gauges flop arms 19 to drop. Current also flows through a line95 to the relay switch 63 which is in neutral position. When the centerblade 89a of switch 89 is moved up into contact with the upper blade890, the current flows through a line 96 to tap 97 in the plug-socket55, then through line 98, terminal 99, to relay 62. It also flows fromtap 97 through line 101 to solenoid 58 to cause the flop arms 19 of theconnected gauges to drop into operative positions.

In use, a sheet 26 of material is inserted into the press brake, asaforesaid, and the press cycles to form the sheet. At it cycles up, thelimit switch 66 is actuated to cause current to flow through line 102,switch 76 and lines 103 and 104 from terminal 92 in the plug-socketassembly 55 to pulse coil 81. This advances the sweep arm 78a to the ltap which is connected by line 105 to the center blade 106 of the secondswitch 89. Each time the press is cycled, the sweep arm 76a advances totaps 2, 3, 4, etc., successively, until the last effective switchdetermined by the setting of the selector switch 107 is actuated.Specifically, in this illustrative disclosure, the selector switch isset at 3, which means three bends are to be performed. This switch hasits taps l 2, 3 connected to taps l, 2", 3, respectively, of the stepperswitch. Thus, after the third bend is made (i.e., tap 2), the stepperswitch is advanced to tap 3 by limit switch 66, and current flows to theselector sweep switch arm 108, leads 109 and 110, to the reset coil 111,which closes the conventional reset mechanism (not shown) to allow thesweep arm 78a to return to 0. The pulse switch 83 allows for the stepperoperation without breaking the circuit to the latch relays 62-69.

A reset switch 112 is connected in parallel with a reset switch 113 inthe front control box 61, both of which are connected through lead 114leading to the reset coil 111; thus at any time during cycling, thesystem can be returned to zero upon actuation of either switch 112 or113.

If desired, a' units and stroke counter can be incorporated into thesystem. The counter is shown at 115 and it has one of its lead connectedto neutral and the other lead to the center blade of unit-cycle switch116, the upper blade (i.e., unit counter position) of which is connectedto the reset switch 112, and its lower blade i.e., stroke counterposition) is connected through a lead 117 with line 84, leading toswitch 76, through which it receives current from limit switch 66. Whenthe counter switch is in unit" position, each time the number of bendsset into the system by the selector has been reachedand the stepperswitch returned to zero, the counter receives a signal and records oneunit having the number of bends set into the system by the selector.When the counter switch'is in its upper or cycle position, each time thepress brake cycles in an up-stroke and the limit switch is actuated, thecounter receives a signal and records one stroke indicating one bend hasbeen made. If one desires to count both units and cycles at the sametime, another counter circuit like the one shown can be added to thesystem parallel to the counter described.

It should be evident thatwhen required additional banks of stepperswitches 78 and'related switches 89 can be added to the system tocontrol additional and other functions of the machine. Such add-onfeatures can be used to program sequential control for tonnage, depthcontrol, ram position and the like where structure is provided in themachine into which the system is incorporated to permit those functions.

While I have described and illustrated a preferred embodiment of myinvention, it should be understood that changes and modifications in thevarious details disclosed can be made without departing from the spiritof the invention, and nothing herein shall be construed as limitationsupon the invention, its concept or structural embodiment as to the wholeor any part thereof, except as defined in the appended claims.

I claim:

1. Gauge control means for a press brake having upper and lower diescomprising, in combination, a plurality of gauges, a flop arm on eachgauge, means operable to move the flop arms into ineffective posi tions,and means to actuate said flop arm moving means.

2. The control means recited in claim 1, in which the gauges areadjustable to carry the flop arms toward and away from the dies, and agauge adjustment member is carried on each flop arm.

3. The control means recited in claim 2, in which the gauge adjustmentmember is a screw bearing microrneter markings.

4. The control means recited in claim 1, in which an accessory fingergauge is carried on the flop arm.

5. The control means recited in claim 1, in which the means foractuating the flop arm moving means comprises an electrical systemincluding a selector switch and a stepper switch.

6. The control means recited in claim 5, in which the electrical systemcan function under manual and automatic control. 7. The control meansrecited in claim 1, in which the gauges are arranged in sets and themeans operable to move the flop arms into ineffective positions isselectively operable to cause movement of the flop arms in selectedsets.

8. The control means recited in claim 1, in which the means foractuating said flop arm moving means includes fluid operated means.

9. The control means recited in claim 8, in which the fluid operatedmeans includes piston-cylinder assemblies one associated with each floparm.

10. The control means recited in claim 1, in which manual control meansfor the moving of selected flop arms into ineffective positions ismounted on the front side of the press brake.

1 1. A gauge fora press brake comprising, in combination, a back bar, anelongated body mounted on the back bar, a flop arm pivotally mounted atoneend to said body, and an adjustable gauge element on the other end ofsaid flop arm, said gauge element being offset from the plane of theflop arm pivot point.

12. The gauge recited in claim 11, in which the flop arm and adjustablegauge element carry complemental index markings.

13. The gauge recited in claim 11, in which the adjustable gauge elementcomprises a screw carrying micro-index markings.

. 14. The gauge recited in claim 13, in which means is provided to lockthe screw adjustment.

15. A gauge for a press brake comprising, in combination, a back bar, anelongated body mounted on the back bar, a flop arm pivotally mounted atone end to said body, a gauge element on the other end of said flop arm,and an auxiliary gauge detachably secured to the flop arm.

16. The gauge recited in claim 15, in which the auxiliary gauge extendsforwardly of the adjustable gauge element.

17. The gauge recited in claim 15, in which the auxiliary gauge has itsfree forward end disposed in a vertical plane.

18. An electric control system adaptable for regulating movement ofgauge flop arms from effectiveto ineffective positions comprising, incombination, a line circuit including a .series of manually setswitches, a stepper switch, a selectorswitch and mechanismcontrolsolenoids, impulse means in the circuit to actuate the stepper switchstep by step so as to deliver current through selected manual switchesto selected solenoids.

19. The control system recited in claim 18, wherein the controlsolenoids function to operate valves in a fluid system connected to theflop arms.

20. The control system recited in claim 18, wherein the solenoids can beselectively actuated independently of said ste er switch.

21. The ontrol system recited in claim 18, in which the circuit includesswitch means operable to permit manual and automatic control of themeans for actuating the gauge flop arms. g

22. Gauge controlmeans for a press brake comprising, in combination, aplurality of gauges, a flop arm pivotally mounted at one end of eachgauge for movement in a vertical plane,a stop face on the free end ofsaid flop arm, said face being below the pivotal mounting, meansoperable to move the flop arm into an ineffective elevated position,andmeans to actuate the flop arm moving means.

23. The method of gauging the size of successive bends to be formed in asheet of material by a press brake having gauges, each gauge comprisinga body and a movable flop arm connected to said'body and havingmechanical means operable to move said flop arms and electrical means toactuate the operable means, comprising the steps of setting a pluralityof gauges in line with a sheet of material to be formed, positioningsaid gauges to define the size of each successive formation, bringingthe sheet of material into contact with the first gauge to make a firstformation, actuating the electrical and mechanical means to move theflop arm of the first gauge into ineffective position, bringing thesheet of material into contact with each next successive effective gaugeto make each respective formation, and actuating the electrical andmechanical means to move the flop arm of each preceding gauge intoineffective position before each successive formation is effected.

24. The method recited in claim 23, with the added step of controllingactuation of the electrical means by switch means actuable by thecycling of the press brake.

25. The method recited in claim 23, with the added step of selectivelyelecting which of the operable means is actuated.

1. Gauge control means for a press brake having upper and lower diescomprising, in combination, a plurality of gauges, a flop arm on eachgauge, means operable to move the flop arms into ineffective positions,and means to actuate said flop arm moving means.
 2. The control meansrecited in claim 1, in which the gauges are adjustable to carry the floparms toward and away from the dies, and a gauge adjustment member iscarried on each flop arm.
 3. The control means recited in claim 2, inwhich the gauge adjustment member is a screw bearing micrometermarkings.
 4. The control means recited in claim 1, in which an accessoryfinger gauge is carried on the flop arm.
 5. The control means recited inclaim 1, in which the means for actuating the flop arm moving meanscomprises an electrical system including a selector switch and a stepperswitch.
 6. The control means recited in claim 5, in which the electricalsystem can function under manual and automatic control.
 7. The controlmeans recited in claim 1, in which the gauges are arranged in sets andthe means operable to move the flop arms into ineffective positions isselectively operable to cause movement of the flop arms in selectedsets.
 8. The control means recited in claim 1, in which the means foractuating said flop arm moving means includes fluid operated means. 9.The control means recited in claim 8, in which the fluid operated meansincludes piston-cylinder assemblies one associated with each flop arm.10. The control means recited in claim 1, in which manual control meansfor the moving of selected flop arms into ineffective positions ismounted on the front side of the press brake.
 11. A gauge for a pressbrake comprising, in combination, a back bar, an elongated body mountedon the back bar, a flop arm pivotally mounted at one end to said body,and an adjustable gauge element on the other end of said flop arm, saidgauge element being offset from the plane of the flop arm pivot point.12. The gauge recited in claim 11, in which the flop arm and adjustablegauge element carry complemental index markings.
 13. The gauge recitedin claim 11, in which the adjustable gauge element comprises a screwcarrying micro-index markings.
 14. The gauge recited in claim 13, inwhich means is provided to lock the screw adjustment.
 15. A gauge for apress brake comprising, in combination, a back bar, an elongated bodymounted on the back bar, a flop arm pivotally mounted at one end to saidbody, a gauge element on the other end of said flop arm, and anauxiliary gauge detachably secured to the flop arm.
 16. The gaugerecited in claim 15, in which the auxiliary gauge extends forwardly ofthe adjustable gauge element.
 17. The gauge recited in claim 15, inwhich the auxiliary gauge has its free forward end disposed in avertical plane.
 18. An electric control system adaptable for regulatingmovement of gauge flop arms from effective to ineffective positionscomprising, in combination, a line circuit including a series ofmanually set switches, a stepper switch, a selector switch and mechanismcontrol solenoids, impulse means in the circuit to actuate the stepperswitch step by step so as to deliver current through selected manualswitches to selected solenoids.
 19. The control sysTem recited in claim18, wherein the control solenoids function to operate valves in a fluidsystem connected to the flop arms.
 20. The control system recited inclaim 18, wherein the solenoids can be selectively actuatedindependently of said stepper switch.
 21. The control system recited inclaim 18, in which the circuit includes switch means operable to permitmanual and automatic control of the means for actuating the gauge floparms.
 22. Gauge control means for a press brake comprising, incombination, a plurality of gauges, a flop arm pivotally mounted at oneend of each gauge for movement in a vertical plane, a stop face on thefree end of said flop arm, said face being below the pivotal mounting,means operable to move the flop arm into an ineffective elevatedposition, and means to actuate the flop arm moving means.
 23. The methodof gauging the size of successive bends to be formed in a sheet ofmaterial by a press brake having gauges, each gauge comprising a bodyand a movable flop arm connected to said body and having mechanicalmeans operable to move said flop arms and electrical means to actuatethe operable means, comprising the steps of setting a plurality ofgauges in line with a sheet of material to be formed, positioning saidgauges to define the size of each successive formation, bringing thesheet of material into contact with the first gauge to make a firstformation, actuating the electrical and mechanical means to move theflop arm of the first gauge into ineffective position, bringing thesheet of material into contact with each next successive effective gaugeto make each respective formation, and actuating the electrical andmechanical means to move the flop arm of each preceding gauge intoineffective position before each successive formation is effected. 24.The method recited in claim 23, with the added step of controllingactuation of the electrical means by switch means actuable by thecycling of the press brake.
 25. The method recited in claim 23, with theadded step of selectively electing which of the operable means isactuated.